It follows the resignation of director-general George Entwistle at the weekend after the programme mistakenly implicated former Conservative treasurer Lord McAlpine in the North Wales children's home scandal of the 1970s and 1980s.

Newsnight was already the subject of an inquiry, by former head of Sky News Nick Pollard, after dropping a report last year which would have examined sex abuse allegations against Jimmy Savile.

In a statement, the corporation said: "To address the lack of clarity around the editorial chain of command, a decision has been taken to re-establish a single management to deal with all output, Savile related or otherwise.

"Helen Boaden has decided that she is not in a position to undertake this responsibility until the Pollard review has concluded.

"During this period Fran Unsworth will act as director of news. In line with this decision, Ceri Thomas will act on a temporary basis as deputy director in place of Stephen Mitchell."

The organisation said it wanted "to make it absolutely clear" that neither Ms Boaden nor Mr Mitchell had anything to do with the failed investigation into Lord McAlpine and they expect to return to their positions after the Pollard report.

Karen O'Connor has been made acting editor of Newsnight after Peter Rippon, who was responsible for the decision to drop the Savile investigation, stepped aside last month.

In another development, Iain Overton, the man whose Tweet alerted the public to the Newsnight programme wrongly linking Lord McAlpine with child abuse, resigned as editor of the Bureau of Investigative Journalism.

Mr Overton had tweeted that a joint report by the Bureau and the BBC was to be broadcast "about a very senior political figure who is a paedophile". His message was retweeted 1,574 times.

Although the programme did not name the politician, it led to speculation on the internet about Lord McAlpine.

Labour MPs are pressing for an urgent statement in the Commons on the crisis. Meanwhile, Tory MP Philip Davies, a member of the Commons Culture, Media and Sport Select Committee, has called for Lord Patten to step down as BBC Trust chairman.

The BBC's acting director-general Tim Davie arrived for work earlier but did not speak to waiting reporters.

Later today he will set out his plans for rebuilding trust in the corporation.

He emailed staff to tell them that BBC management will pull together as one team to tackle the problems "head on".

It came as the Prime Minister stepped into the row over Mr Entwistle's pay-off - a full year's salary of £450,000 in lieu of notice after just 54 days in the post. Downing Street said David Cameron thinks the amount was "hard to justify", though it was a matter for the BBC Trust to decide.

Under the terms of Mr Entwistle's contract he was entitled to only six months' pay but the trust said the additional payment had been agreed as a reflection of his continuing involvement with the various BBC inquiries now under way.

Mr Cameron also expressed his support for Lord Patten as chairman of the BBC Trust..

On Sunday, Mr Davie received a report which Mr Entwistle had commissioned from BBC Scotland director Ken MacQuarrie into how Newsnight came to wrongly implicate Lord McAlpine.

Before he quit, Mr Entwistle warned it could result in disciplinary action against staff.